The U.S. Justice Department pressed ahead with its antitrust case against Google Wednesday, questioning a former employee of the search engine giant about deals he helped negotiate with phone companies in the 2000s. Chris Barton, who worked for Google from 2004 to 2011, testified that he made it a priority to negotiate for Google to be the default search engine on mobile devices. In the biggest antitrust case in a quarter century, the government is arguing that Google has rigged the market in it